Long-Haul Flights: What Contact Lens Wearers Should Pack in the Cabin

Cabin relative humidity below 20% is the norm. Newer aircraft like the Boeing 787 and Airbus A350 raise humidity to 15~25%, but cabins on older aircraft have been measured at 4~7%, with cockpit and first-class areas sometimes recorded even lower. Contact lenses are a thin film sitting on the tear film, so they lose moisture easily in this kind of dryness, and the American Academy of Ophthalmology (AAO) recommends removing lenses on long flights if there's any chance of falling asleep. Here's a rundown of what lens wearers should pack and how to handle it step by step, including liquid carry-on rules.

How low does cabin humidity actually get

Boeing states that the 787 raises humidity to 15~25%, up from the 4~7% typical of previous-generation aircraft. Conversely, older aircraft or high-altitude flights with low cabin traffic have been reported to drop as low as 1% humidity. Cockpit and crew areas typically sit around 2~3%, with some measurements showing conditions drier than the Sahara Desert.

When humidity is low, the tear film's water layer evaporates first, and lenses tend to draw moisture back out of the eye to compensate, which means lens wearers feel dryness faster than non-wearers. Regardless of seat class or aircraft age, any segment over 4 hours should be treated as a condition requiring some kind of response.

When and why you should remove your lenses

The American Academy of Ophthalmology advises removing lenses on flights where there's a chance of falling asleep, noting that sleeping with lenses in raises the risk of eye infection by 6 to 8 times. Even while awake, wearing lenses when the tear film isn't stable only increases discomfort.

When you take your lenses out, always store them in a lens case filled with sterile solution. Don't leave them in a cup, since there have been cases of flight attendants mistaking a cup for trash and throwing lenses away along with it. Soaking lenses in water is also off-limits: water isn't sterile, and depending on the country, it may contain bacteria that can lead to serious eye infections.

For this reason, lens wearers should make it standard practice to always pack prescription glasses in their carry-on bag.

Carry-on rules for solution and artificial tears

Lenses and lens cases themselves don't count as liquids, so there's no limit on quantity and they can go in either checked or carry-on baggage. The issue is cleaning/storage solution and artificial tears. At Incheon International Airport, liquids and gels must be in individual containers of 100ml or less and packed into a single 1L clear zip bag to be allowed in the cabin, a standard that applies across most international airports.

The US TSA similarly classifies contact lens solution and rewetting drops as liquids, applying the 3.4-ounce (100ml) container and zip-bag rule. However, if the amount is medically necessary, containers over 100ml may be allowed through if declared at the checkpoint, though the final call rests with the security officer on site, and items that trigger an alarm may not pass. The TSA recommends packing solution over 100ml in checked luggage.

Most commercially sold solution bottles are large-format, in the 240~355ml range, which doesn't meet the 100ml rule. Before traveling, either buy a separate small container of 100ml or less, or transfer solution into a smaller container to avoid problems at the checkpoint.

The AAO also recommends packing an extra bottle of solution separately in case of leaks.

Small travel-size lens rewetting solution in 15ml bottles can be purchased on Coupang.

How to choose artificial tears for in-flight use

If you plan to keep wearing lenses in-flight and manage dryness as it comes up, preservative-free single-use artificial tears are the standard choice. According to the Namuwiki entry on artificial tears, multi-use products containing preservatives (benzalkonium chloride) should be limited to 4 to 6 uses per day, while preservative-free single-use products can be used more often as needed.

According to material citing an ophthalmology professor at Korea University Anam Hospital, the appropriate daily frequency for artificial tears is 2 to 6 times, with up to 8 times considered acceptable, but this figure applies to products containing preservatives, and preservative-free single-use products aren't bound by this limit. In situations like long-haul flights where you may need to apply drops more than 6 times, choosing single-use individual units aligns both with the regulations and with preventing eye irritation.

Preservative-free single-use artificial tears in individually packaged units are available at Olive Young.

The option of switching to daily disposable lenses

If you fly frequently or have a trip that includes a long-haul segment, it's worth considering switching to daily disposable lenses just for the duration of the trip. Since daily lenses are replaced with a fresh pair every day, no storage solution is needed at all, which frees you from the liquid carry-on rules. Ophthalmology resources also note that daily disposable lenses are often recommended for people who wear lenses only occasionally.

If you normally wear biweekly or monthly lenses, getting a separate prescription for daily disposables just for the trip is a way to reduce both luggage bulk and time spent at the security checkpoint.

Sources: Simple Flying: The Boeing 787's Unique Cabin Design That Reduces Jet Lag

Sources: ALPA: While Humid Conditions May Impact Aircraft Performance

Sources: American Academy of Ophthalmology, Eye Care Tips for Travelers

Sources: American Academy of Ophthalmology, Glasses & Contacts

Sources: TSA, Contact Lenses

Sources: Incheon International Airport, Guide to Restricted Carry-On Items

Sources: Namuwiki, Artificial Tears